Different Colours and Meanings of Highway Signs Warning signs are wont to alert highway, street or road users to unexpected or dangerous conditions ahead which may involve a discount of speed, situations which may not be readily apparent, or an action within the interest of safety and efficient traffic operations like a curve, detour, sideroad, etc. they typically have a yellow or orange background with black symbols or letters on a diamond-shaped or rectangular sign. Yellow pennant-shaped signs caution motorists where passing is unsafe. Round yellow warning signs alert motorists that there is a railroad crossing ahead.
Warning signs are made with the very best quality .080 aluminum, coated with the industries best 3M or Avery reflective sheeting and printed to last beyond the sheeting warranty.